/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:		arm_cmplx_mag_squared_f32.c
*
* Description:	Floating-point complex magnitude squared.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
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*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* ---------------------------------------------------------------------------- */
#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @defgroup cmplx_mag_squared Complex Magnitude Squared
 *
 * Computes the magnitude squared of the elements of a complex data vector.
 *
 * The <code>pSrc</code> points to the source data and
 * <code>pDst</code> points to the where the result should be written.
 * <code>numSamples</code> specifies the number of complex samples
 * in the input array and the data is stored in an interleaved fashion
 * (real, imag, real, imag, ...).
 * The input array has a total of <code>2*numSamples</code> values;
 * the output array has a total of <code>numSamples</code> values.
 *
 * The underlying algorithm is used:
 *
 * <pre>
 * for(n=0; n<numSamples; n++) {
 *     pDst[n] = pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2;
 * }
 * </pre>
 *
 * There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
 * @addtogroup cmplx_mag_squared
 * @{
 */


/**
 * @brief  Floating-point complex magnitude squared
 * @param[in]  *pSrc points to the complex input vector
 * @param[out]  *pDst points to the real output vector
 * @param[in]  numSamples number of complex samples in the input vector
 * @return none.
 */

void arm_cmplx_mag_squared_f32(
    float32_t *pSrc,
    float32_t *pDst,
    uint32_t numSamples)
{
    float32_t real, imag;                          /* Temporary variables to store real and imaginary values */
    uint32_t blkCnt;                               /* loop counter */

#ifndef ARM_MATH_CM0_FAMILY
    float32_t real1, real2, real3, real4;          /* Temporary variables to hold real values */
    float32_t imag1, imag2, imag3, imag4;          /* Temporary variables to hold imaginary values */
    float32_t mul1, mul2, mul3, mul4;              /* Temporary variables */
    float32_t mul5, mul6, mul7, mul8;              /* Temporary variables */
    float32_t out1, out2, out3, out4;              /* Temporary variables to hold output values */

    /*loop Unrolling */
    blkCnt = numSamples >> 2u;

    /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
     ** a second loop below computes the remaining 1 to 3 samples. */
    while(blkCnt > 0u)
    {
        /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
        /* read real input sample from source buffer */
        real1 = pSrc[0];
        /* read imaginary input sample from source buffer */
        imag1 = pSrc[1];

        /* calculate power of real value */
        mul1 = real1 * real1;

        /* read real input sample from source buffer */
        real2 = pSrc[2];

        /* calculate power of imaginary value */
        mul2 = imag1 * imag1;

        /* read imaginary input sample from source buffer */
        imag2 = pSrc[3];

        /* calculate power of real value */
        mul3 = real2 * real2;

        /* read real input sample from source buffer */
        real3 = pSrc[4];

        /* calculate power of imaginary value */
        mul4 = imag2 * imag2;

        /* read imaginary input sample from source buffer */
        imag3 = pSrc[5];

        /* calculate power of real value */
        mul5 = real3 * real3;
        /* calculate power of imaginary value */
        mul6 = imag3 * imag3;

        /* read real input sample from source buffer */
        real4 = pSrc[6];

        /* accumulate real and imaginary powers */
        out1 = mul1 + mul2;

        /* read imaginary input sample from source buffer */
        imag4 = pSrc[7];

        /* accumulate real and imaginary powers */
        out2 = mul3 + mul4;

        /* calculate power of real value */
        mul7 = real4 * real4;
        /* calculate power of imaginary value */
        mul8 = imag4 * imag4;

        /* store output to destination */
        pDst[0] = out1;

        /* accumulate real and imaginary powers */
        out3 = mul5 + mul6;

        /* store output to destination */
        pDst[1] = out2;

        /* accumulate real and imaginary powers */
        out4 = mul7 + mul8;

        /* store output to destination */
        pDst[2] = out3;

        /* increment destination pointer by 8 to process next samples */
        pSrc += 8u;

        /* store output to destination */
        pDst[3] = out4;

        /* increment destination pointer by 4 to process next samples */
        pDst += 4u;

        /* Decrement the loop counter */
        blkCnt--;
    }

    /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
     ** No loop unrolling is used. */
    blkCnt = numSamples % 0x4u;

#else

    /* Run the below code for Cortex-M0 */

    blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

    while(blkCnt > 0u)
    {
        /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
        real = *pSrc++;
        imag = *pSrc++;

        /* out = (real * real) + (imag * imag) */
        /* store the result in the destination buffer. */
        *pDst++ = (real * real) + (imag * imag);

        /* Decrement the loop counter */
        blkCnt--;
    }
}

/**
 * @} end of cmplx_mag_squared group
 */
